ToDtoGenerator.java

/*******************************************************************************
 * Copyright (c) 2017 Red Hat.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Red Hat - Initial Contribution
 *******************************************************************************/
package org.eclipse.che.api.languageserver.generator;

import org.eclipse.lsp4j.jsonrpc.messages.Either;

import java.io.PrintWriter;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.List;
import java.util.Map;
import java.util.Set;

import static org.eclipse.che.api.languageserver.generator.DtoGenerator.INDENT;
import static org.eclipse.che.api.languageserver.generator.DtoGenerator.dtoName;

;

/**
 * This class generates property conversions from regular lsp4j classes to dto classes.
 * Used to convert responses from the backend language servers for che rmi usage.
 *
 * @author Thomas Mäder
 */
public class ToDtoGenerator extends ConversionGenerator {

    private Set<Class<? extends Object>> classes;

    public ToDtoGenerator(Set<Class<? extends Object>> classes) {
        this.classes = classes;
    }

    public static void generateMakeDto(String indent, PrintWriter out, Set<Class<? extends Object>> classes) {
        out.println(indent + "public static final Object makeDto(Object obj) {");
        for (Class<? extends Object> clazz : classes) {
            out.println(indent + INDENT + String.format("if (obj instanceof %1$s) {", clazz.getName()));
            out.println(indent + INDENT + INDENT + String.format("return new %1$s((%2$s)obj);", dtoName(clazz), clazz.getName()));
            out.println(indent + INDENT + "}");
        }
        out.println(indent + INDENT + "return obj;");
        out.println(indent + "}");
    }

    public void generateToDto(String indent, PrintWriter out, Class<?> receiverClass, Method m, String objectName) {
        String varName = fieldName(m) + "Val";
        String valueAccess = objectName + "." + getterName(receiverClass, m) + "()";
        Type paramType = m.getGenericParameterTypes()[0];
        if (getRawClass(paramType).isPrimitive()) {
            generateToDto(indent + INDENT, out, varName, valueAccess, paramType);
            out.println(String.format(indent + INDENT + "%1$s((%2$s)%3$s);", m.getName(), paramType.getTypeName(), varName));
        } else {
            out.println(indent + String.format("if (%1$s == null) {", valueAccess));
            out.println(indent + INDENT + String.format("%1$s((%2$s)null);", m.getName(), paramType.getTypeName()));
            out.println(indent + "} else {");
            generateToDto(indent + INDENT, out, varName, valueAccess, paramType);
            out.println(String.format(indent + INDENT + "%1$s((%2$s)%3$s);", m.getName(), paramType.getTypeName(), varName));
            out.println(indent + "}");
        }
    }

    private void generateToDto(String indent, PrintWriter out, String varName, String valueAccess, Type paramType) {
        Class<?> rawClass = getRawClass(paramType);
        if (List.class.isAssignableFrom(rawClass)) {
            generateListConversion(indent + INDENT, out, varName, valueAccess, paramType);
        } else if (Map.class.isAssignableFrom(rawClass)) {
            generateMapConversion(indent + INDENT, out, varName, valueAccess, paramType);
        } else if (Either.class.isAssignableFrom(rawClass)) {
            generateEitherConversion(indent + INDENT, out, varName, valueAccess, paramType);
        } else {
            out.println(String.format(indent + "%1$s %2$s = %3$s;", rawClass.getName(), varName,
                                      dtoValueExpression(rawClass, valueAccess)));
        }
    }

    private void generateEitherConversion(String indent, PrintWriter out, String varName, String valueAccess,
                                          Type paramType) {
        String innerName = varName + "e";

        out.println(indent + String.format("%1$s %2$s;", paramType.getTypeName(), varName));
        out.println(indent + String.format("if (%1$s.getLeft() != null) {", valueAccess));
        generateToDto(indent + INDENT, out, innerName, valueAccess + ".getLeft()", EitherUtil.getLeftDisjointType(paramType));
        out.println(indent + INDENT + String.format("%1$s= Either.forLeft(%2$s);", varName, innerName));
        out.println(indent + "} else  {");
        generateToDto(indent + INDENT, out, innerName, valueAccess + ".getRight()", EitherUtil.getRightDisjointType(paramType));
        out.println(indent + INDENT + String.format("%1$s= Either.forRight(%2$s);", varName, innerName));
        out.println(indent + "}");
    }


    private void generateMapConversion(String indent, PrintWriter out, String varName, String valueAccess,
                                       Type paramType) {
        ParameterizedType genericType = (ParameterizedType)paramType;
        Type containedType = genericType.getActualTypeArguments()[1];
        Type valueType = genericType.getActualTypeArguments()[1];
        String containedName = varName + "X";
        out.println(indent + String.format("HashMap<String, %1$s> %2$s= new HashMap<String, %3$s>();",
                                           containedType.getTypeName(), varName, containedType.getTypeName()));
        out.println(String.format(indent + "for (Entry<String, %1$s> %2$s : %3$s.entrySet()) {",
                                  valueType.getTypeName(), containedName, valueAccess));
        generateToDto(indent + INDENT, out, varName + "Y", containedName + ".getValue()", valueType);
        out.println(indent + INDENT
                    + String.format("%1$s.put(%2$s, %3$s);", varName, containedName + ".getKey()", varName + "Y"));
        out.println(indent + "}");

    }

    private void generateListConversion(String indent, PrintWriter out, String varName, String valueAccess,
                                        Type paramType) {
        Type containedType = containedType(paramType);
        out.println(indent + String.format("ArrayList<%1$s> %2$s= new ArrayList<%3$s>();", containedType.getTypeName(), varName,
                                           containedType.getTypeName()));
        String containedName = varName + "X";
        out.println(String.format(indent + "for (%1$s %2$s : %3$s) {", containedType.getTypeName(), containedName,
                                  valueAccess));
        generateToDto(indent + INDENT, out, varName + "Y", containedName, containedType);
        out.println(indent + INDENT + String.format("%1$s.add(%2$s);", varName, varName + "Y"));
        out.println(indent + "}");
    }


    private String dtoValueExpression(Class<?> t, String value) {
        if (isDtoClass(t)) {
            return String.format("new %1$s(%2$s)", dtoName(t), value);
        } else {
            return String.format("(%1$s)makeDto(%2$s);", t.getName(), value);
        }
    }

    private boolean isDtoClass(Class<?> t) {
        return classes.contains(t);
    }

}